Often when I use a pencil sharpener a lot, the pencil shavings and lead gets jammed in the sharpener part. What's an efficient way of cleaning it out?
I assume you mean a conventional compact manually-operated prism sharpener like this:
Thanks Asim18 at Wikipedia!
To remove anything lodged between the blade and casing, use a thin metal instrument (like the tip of a mechanical pencil, or back of a hobby knife). Put it in the slit between the blade and casing, and use it to push stuff out toward the opening.
To remove any left-over dirt inside the cone, put a piece of tissue or toilet paper over the end of a pencil, and "sharpen" it anti-clockwise (the opposite direction compared to the usual sharpening motion, to avoid tearing the tissue). If the dirt is sticky (e.g. some fool tried to sharpen an oil-based crayon), try isopropanol.